


Becoming Sisters

by Rivulet027



Category: Supergirl (TV 2015)
Genre: Adopted Sibling Relationship, Gen, Protective Siblings
Language: English
Status: Completed
Published: 2017-05-29
Updated: 2017-05-29
Packaged: 2018-11-06 06:22:00
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,024
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11030433
Author URL: https://archiveofourown.org/users/Rivulet027/pseuds/Rivulet027
Summary: Alex was fine being an only child. She's not sure she wants to be a sister.





	Becoming Sisters

**Author's Note:**

  * For [flipflop_diva](https://archiveofourown.org/users/flipflop_diva/gifts).



> Disclaimer: I own nothing to do with Supergirl. It's not my toy box and I'm merely playing.

Alex doesn’t want to be an older sister. Alex is just fine being an only child. Her friends agree.

“If my parents brought some strange girl home out of no-where without discussing it with me I’d be so angry!”

The problem is they did discuss it with her, at length. She said she could handle this. She said she could be mature about this, helping a girl from another planet, who’d just lost her entire planet, adjust to life on Earth. She just didn’t realize that Kara would be so new to everything, so delighted by everything new she was learning during the day. She didn’t realize that other girl would be so miserable at night, trying to quietly mourn the planet, the people she'd lost. Alex isn’t sure how to react. At first she’d tried to give Kara space, tried not to be too embarrassed by her. Now she holds the other girl when she cries, but she still find Kara embarrassingly naive.

She’s jealous too, Alex can admit that. Kara has powers, the same ones as Superman. How many other girls get to live with Superman’s cousin? Kara doesn’t even seem to appreciate that she's Superman's cousin. She listens about her powers with rapt attention then learns each one of them and how to hide them.

Sometimes, just sometimes, she’ll take Alex flying. Alex wants to be her sister then, but knows she’s being selfish.

Alex knows she’s not mature enough to handle being a big sister to an alien with superpowers who lost her whole planet. It’s not fair that her parents asked.

It’s also not fair that Kara gets to spend the whole day with Superman, doing mundane, not superhero things, like getting to know one another. Kara always comes back quiet too. It’s further proof that Kara is just so weird. Who comes back from spending a day with a superhero upset?

Alex comes back from spending an afternoon with her friends, totally not internally pouting about not even getting introduced to Superman, to find Kara hiding in the closet. She’s also got Alex’s science text book open in her lap and is correcting things, again.

“Really?” Alex demands.

“It’s wrong,” Kara insists.

“It can’t be that wrong,” Alex disagrees. “Not wrong enough that you have to ruin my text book.”

“It is. You should know things the right way, not this…this…”

Kara looks like she’s ready to cry and it’s daylight out. Alex isn’t sure she’s ready to handle daylight tears or a sad so big it can’t be held in until night time crying and hugs. Alex bites her lips to keep from yelling at her. They are not going to have another argument, not when Kara looks like she’s ready to cry.

Alex is also completely unprepared for how much she suddenly wants to yell at Superman. What did he do that made Kara so upset? Alex huffs and stomps her feet and tries to reign this anger in. She can be mature, she can. With an exclamation of impatience she spins on her heels and makes her way to their desk before yanking open the bottom drawer and pulling out a new notebook. She dumps the notebook in Kara’s lap and tells her. “Write it down here instead of ruining my textbook. I don’t want our parents to have to pay for it at the end of the year.”

Kara stares at her, eyes gone big.

“What?”

Kara opens her mouth, but nothing comes out. She pulls the notebook close and stares down at the text book.

“Stay here,” Alex tells her before stomping downstairs. Her mother asks questions, but Alex isn’t sure what to say other than Kara is having a bad day. She’s not sure why this is upsetting her so much. She tries not to examine it, instead lets the feeling settle in her gut as she waits for the popcorn she puts into the microwave to finish popping. She dumps it into a bowl, tells her mom that no the two of them don’t need anything and makes her way back upstairs. Kara is writing fiercely in the notebook. Alex scoots into the space left in the closet and offers Kara the bowl of popcorn. Kara chews on her bottom lip.

“What?”

“Our parents?” Kara asks softly.

Alex blinks. She did say that. She frowns. Maybe she’s more okay with this sister thing than she thought. Alex shrugs. “They asked. I agreed to share. I’m probably not very good at it, but I’ll get there.”

“You don’t hate me?”

“If I hated you I wouldn’t be mad at him for upsetting you,” she tries to explain.

Kara shakes her head. “It’s not his fault.”

“What’s not his fault?” Alex asks suspiciously.

“There’s so much he doesn’t know, about our world, so much he wants to know and I’m younger than him.”

Kara’s eyes are filling with tears.

“I don’t understand,” Alex admits.

“He was supposed to be a baby. I was supposed to look out for him, not the other way around,” Kara tells her plaintively. “I know it’s stupid to be upset about it, but I am.”

Alex stares, then says slowly. “Let me see if I have this right. Your parents were going to send you here with a baby to raise.”

Kara nods.

“By yourself? On a whole new planet where the two of you would end up with superpowers that you knew nothing about before you got here?”

Kara nods again.

Alex stares. Of all the stupid things she’s ever heard of! Maybe her parents weren’t asking a lot from her. Maybe Kara’s parents were jerks. She’s not about to say that to Kara though. Alex sighs and sets the popcorn aside. Kara makes a mournful noise looking at it. Alex pulls the book and notebook out of Kara’s hand, then pulls Kara into a hug. Kara sinks down against her with a sigh. Alex pats her on the back, then pulls the popcorn close again. She doesn’t really know how to be a sister, yet, but she’s willing to learn, because clearly Kara needs her.

**Works inspired by this one:**

  * [Sisters (The Mission Remix)](https://archiveofourown.org/works/12112527) by [navaan](https://archiveofourown.org/users/navaan/pseuds/navaan)




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